Well-drilling bit



evident hereinafter.

'rial from the flat bottom of the hole.

- i,sszsee PATENT' oFFic.

eng T. Patron, or Loire Buscar, caniroaivia.

I l WELL-DRILLING Brr.

Application filed January 5, 1924. Serial No. 684,555.

To all whom z't may concern.' Be it known that I, GUY T. PRYOR, a citizen of the United States, residing at Long Beach, in the county of Los Angeles, State of California, have invented a new and useful Nell-Drilling Bit, of which the followl ing is a specification.

lhis invention relates to Well drilling equipment of the character now extensvely employed in the drilling of oil wells.

The subterranean formations which must be penetrated in order to reach the bodies of oil vary greatly in character, and various types of tools must be employed in order to accomplish the drilling speedily and in a satisfactorymanner. The fish tail bit which is extensively used in rotary well drilling provides a cutting edge which lies in a plane perpendicular to the axis of the hole being drilled. ln other words, the intended action vof the drill is that the drilling of the hole shall be accomplished by removal of matle- T ie coiners on the sh tail bit are soon worn off `and the gauge of thev bore lost, thus making reaming of the hole frequently necessary.`

It is an object of my invent-ion to provide 4a well drilling bit having cutting edges which are conically disposed and which bit is arranged to preserve the gauge of the bore for a maximum period of time.

It isa further object of the invention to provide a drill bit which will operate satis-- factorily in plastic materials, such as shale and certain forms of clay which adhere to the drilling tool and interfere with the drilling action.

It is a further object of the invention to provide a well drilling bit having the inherent tendency to follow a straight path. This bit is, of conical form and is provided with helical cutting blades the cutting edges of which are suitably notched or interrupted to give a self-clearing effect in soft materials. y

It is a further object of the invention to provide'a well drilling bit of this character having -the cutting blades deeply undercut so that the sharpness of the blade will be maintained, and for providing ample exterior passages for the upward circulation of the lubricating mud delivered under pressure near the point of the bit.

The especial advantages of the invention and further objects thereof will be made drilled openings 21 which,

Referring to the drawing which is for illustrative purposes only,

Fig. is an elevation of a well drilling bit embodying the features of my invention.

Big. 2 is a plan View taken from Fig. 1. Fig. 3 is a fragmentary section taken on a plane represented by the line 3 3 of Fig. 2.

Fig. 4 is a section taken on a plane indicated by the line 4 4 of Fig. 1. Fig. 5 is a View illustrating a use of the invention.

Fig. 6 is a view illustrating another use. of the invention.

The, form of my invention shown in the drawing employs a tool joint pin 11 from which there downwardly extends a body 12 V having a pluralityof cutting oblades 15 which are of conical spiral form, as shown. It is convenient to use three of the cutting blades 15, as illustrated, but conditions may be found .wherein it may be desirable to employ a different number of cutting blades. As shown in Figs. 2 and 4, the blades are formed of material such as steel disposed between spiral surfaces 16 and 17, thus giving the blade a deep spiral undercut in such a manner that passages or grooves 19 are of .sufiicient size for the passage of the circulating liquid and cuttings.

The circulation of mud employed for lubricating and mudding up purposes isestab- `lished through a central opening 20, which extends downwardly through the body 12 of the drill and communicates with laterally as shown in Figs. 5 and 6, are disposed near thev lower end of the drill so that the cuttings will be caught and carried upwardly by the circulating fluid. This circulating fluid also serves to wash out the passages 19 between the blades 15. The blades 15, as shown in'Fig. 1, are equipped with notches 25` which give the cutting edges 26 of the blades an interrupted effect. The notches 25 are staggered or offset with relation to each other, sothat the entire surface of the conical hole being drilled by the cutting edges will be traversed by a cutting edge.

It will be perceived that the cutting action of theV bit, instead of extending across the flat bottomoface of the hole being bored, is distributed over a considerably longer coni- 'cal face, the gauge of the hole being established by the diameter across the upper ends of the blades 15. The use of the notches 25 interrupting the cutting edges of the blades lll wedges into the narrow cuts 31 formed at the upper end of each blade, as shown in Fig. 3, thus forcing the portions 30 of the blades outwardly as indicated by the dotted lines 32.

When it is found impossible to remove a tool or obstruction from a well, it becomes necessary to side-track the hole, that is, to drill to one side of obstruction. My bit is especially adapted to this use as the point 35 thereof, Fig. 2, may be readily caused to eut to the side of Aan obstruction such as a dill pipe 36 lost in a previously bored hole 3 The invention, as shown in Fig. 6, is also particularly adapted to the penetrating of the cement plug 39 formed at the lower end of a casing 40 when the casing is cemented in, either for the purpose of secluding water or securing the casing preliminary to bringing the well into production. An additional advantage of this drilling tool resides in the eentralizing eii'ect resulting from the conoidal form thereof. The drill in operation seats in a conoidal recess and is prevented thereby from lateral movement, from which an irregularity in a well drilled by a rotary sh tail bit is often produced.

I- claim as my invention:

`l. A well drilling bit comprising: a central body having interrupted conoidal helical blades formed thereon and having a longitudinal central opening, said blades being widest. at the top and there wider than the actuating shaft and being also spirallyundercut to provide circulation passages to which a circulatin liquid may be fed through laterals from said longitudinal central opening.

2. A well drilling bit comprising: a central body having interrupted conoidal helical blades formed thereon, said blades being' tion passages, there being a circulation passage extending downwardly through said body and opening near the lower end thereof into said circulation passages provided by undercutting.

4. A well drilling bit comprising: a central body having conoial helical blades formed thereon, in which notches are out to provide an interrupted effect in the cutting edges of said blades, 'saidy blades being widest at the top and there wider than the actuating shaft and being also spirally undercut to provide circulation passages.

5. A well drilling bit comprising: a body having longitudinal blades formed thereon and means for re-establishing the gauge of said bit consisting of transverse slots extending inward from the upper ends of said blades to permit spreading of said` blades radially apart from said body by the insertion of wedges. l

6. A well drilling bit comprising a bit carrying interrupted and downwardly diminishing undercut spiral blades, each blade being provided with means for delivering circulating fluid immediately in advance thereof and with means for increasing, by

the insertion of a wedge, the lateral extension 0f its uppermost and widest part.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 29th day of December, 192

GUY T.v PRYOR. 

